Good to see you back and thank you for a thoughtful response once again. 

>For example, a person with Alzheimer's or cognitive impairment could use Alexa, which would alleviate the burden on caregivers, and robotics also contributes in this regard.

This reminds me of something I've heard a few times about loss of hearing being a contributing factor with some for decline into dementia. Without physical connection this would be an even bigger isolator that even something like Alexa wouldn't help with. I actually have a client with Alzheimer's and as his dementia has advanced he is needing more physical care to assist and guide him. It has become a risk to leave him alone. So while AI and robotics might offer some assistance it will likely not replace other people at least for a while. 

>sometimes, the bonds we forge with other people can lead us to desire periods of isolation

Very true. Not everyone is comfortable with constant company and sometimes you might want to have people around without necessarily having to interact with them. I was recently discussing this with my daughter. We also touched on codependency and whether it's a good or bad thing. Relationships where we make up for the other's weaknesses with our strengths are surely a good thing, unless the relationship is causing a toxic dependency where we are using the other or being used by them as a crutch. Like many things there should probably be a middle ground. 

>I've managed to set limits to pursue other activities. And, paradoxically, these limits can be counterproductive when socializing outside the digital space, as I find others absorbed in their cell phones.

Yes, this is certainly a conundrum which can leave you feeling isolated while surrounded by people who are each absorbed in their own digital space. Thankfully my interest is climbing which doesn't exactly allow for being absorbed on a screen. You can regularly end up talking with strangers while you're working on a climb at the same time. People often express what a wonderfully supportive community exists at the climbing gym. I usually go with my daughter, but even when I've gone alone and there have been no familiar faces I'll end up chatting with someone, making a new familiar face for another time when we can cross paths again.